1. Field of the Invention
This invention generally relates to an apparatus for examining a wheel of a vehicle, and in particular to a wheel alignment examining apparatus using rollers to clamp a wheel. More specifically, the present invention relates to a wheel alignment examining apparatus capable of examining alignment and/or performance of a wheel statically and/or dynamically.
2. Description of the Prior Art
A wheel alignment examining apparatus for examining the mounting condition of a wheel of a vehicle, such as an automobile, is well known in the art. Various parameters are set for a wheel mounted on a vehicle, such as an automobile, and they include the so-called wheel inclination parameters, such as toe, camber and caster, in relation to running performance. These wheel inclination parameters are checked before a vehicle is sent to a market upon its completion, and they are also checked after repair of a vehicle, such as replacement of wheels. In order for a vehicle to have an excellent running performance, it is important that such wheel inclination parameters be set and maintained at proper values. In addition, the dynamic performance of a wheel, i.e., the performance while a wheel is in rotation, includes such parameters as the amplitude of wiggling of a wheel and the steered angle of a wheel, and since the running performance of a vehicle is also significantly affected by such a dynamic performance, it is also important to be able to examine the dynamic performance of a wheel at high accuracy.
The prior art approaches for measuring the toe and/or camber of a wheel while maintaining the wheel in rotation are disclosed in Japanese Patent Laid-open Publications, Nos. 51-83301 and 54-49701. In accordance with these prior art approaches, a wheel to be examined is supported on a pair of rollers for rotation; however, the wheel to be examined is either not supported at its side surfaces, or a contact roller is brought into rolling contact with one side surface of the wheel. In accordance with these prior art approaches, since a wheel to be examined is not clamped at opposite side surfaces, the geometrical center of the wheel is not determined and thus it is difficult to carry out an accurate measurement.
Japanese Patent Applications Nos. 58-109235 and 59-9502 and Japanese Patent Laid-open Publication No. 61-41913, assigned to the assignees of the present application, disclose a technique for determining the geometrial center of a wheel supported on a floating table by holding the wheel from both side surfaces thereof. However, in accordance with this approach, since the wheel to be examined is supported on a table, the wheel cannot be rotated so that only the static performance can be measured. More importantly, these prior applications only teach to clamp a wheel from both sides using a slider which comes into a surface contact with one side surface of the wheel.
As set forth above, none of the prior art allows to measure both of the dynamic and static performances of a wheel as being mounted on a vehicle completely. Under the circumstances, there has been a need to develop a more perfected apparatus for examining a wheel of a vehicle.